Frames for fire-retarding and fire-proof doors



United States Patent FRAMES-FOR FlRE-RETARDING AND FIRE-PROOF DOORS Jens C.v Snitker, Risskov, Denmark, assignor to S.O.S. B-Skod I/S, Aarhus, Denmark, a Danish partnership Application January 22, 1957, Serial No. 635,410

Claims priority, application Denmark January 28, 1956 11 Claims. (Cl. 20---11) The invention relates to frames of combustible material for fire-retarding and fire-proof doors.

Doors are known which have been made fire-retarding by providing in the middle of the door between its lateral faces an inlay or a layer of incombustible material which extends to the edges of the door, whereas the door otherwise consists of wood. In their appearance such doors do not differ from ordinary wooden doors and are therefore suitable for use in dwelling houses and in such places, where aesthetic considerations matter. If the door is placed in an ordinary wooden frame, however, the frame will burn through before the 'door in case of fire.

One object of the present invention is to indicate such an arrangement of the frame that it will be at least as fire-proof as a door constructed as indicated above.

Another object of the invention is to indicate special means to prevent the fire from spreading through the chink between the door and the frame, which chink in the course of time or during the fire itself may open as a consequence of the warping of the wooden material, and through the space, if any, between the frame and the surrounding wall.

A- further object is to provide a frame of the kind in question, which will be strong and durable and have a near appearence.

With the above and other objects in view of the present invention consists in the combination and arrangement of parts, hereinafter more fully described, illustrated in the accompanying drawings and more specifically pointed out in the claims, it being understood that changes may be made in the form, size, proportions, and details of construction without departing from, or sacrificing any of the advantages of the invention.

In the drawings.

Fig. 1 is a side-view of a door with surroundingframe,

Fig. 2 shows on a larger scale a cross section of the frame on the line II-II in Fig. 1,

Fig. 3 is a cross section through an altered embodiment, and

Fig. 4 is a similar cross section, showing an arrangement of some paste grooves used in connection with the invention.

According to Fig. l a fire-retarding or fire-proof door is suspended in a frame 12 of wood or wooden material by means of hinges 14. In the usual way the frame consists of three frame-pieces surrounding the door 10 at both side edges and at the hop edge. The numeral 16 denotes an ordinary door-handle.

In the embodiment shown in Fig. 2 the frame 12 consists of two wooden layers 18 and 20 glued together. In the layer 18 there is milled a low and wide groove, wherein a body of an incombustible material has been arranged, which said material may e.g. be in the form of a strip 22 of asbestos or other inorganic material, which is incombustible as well as heat insulating. The said strip is wholly embedded in the wood and as it extends through part of the depth of the frame only, the layers 18 and 20 will ice be in direct contact at both edges of the strip 22, thus making it possible to obtain a reliable agglutination of the said layers. It will be understood that the strip 22 extends longitudinally through each of all three framepieces.

As usual the frame is provided with a rebate which is engaged by the border of the door 10, when the latter is closed. This rebate has a face 24 which constitutes an abutment for the door, and a face 26 which is approximately at right angles to the face 24 and which surrounds the edge 28 of the door at a slight distance, determined by practical conditions, whereby an ordinary chink 30 is produced. In the abutment face 24 there is produced a groove with approximately V-shaped cross section, wherein a foam-producing putty or paste 32 has. been placed in a manner known per se.

This paste may e.g. consists of. ammonium phosphate of ammonium monohydrogen phosphate and 35% of ammonium dihydrogen phosphate), mixed with three parts of sugar, e.g. in the form of icing sugar, refined loafsugar or syrup, and two parts of gum arabic. The mixture is stirred in water to a suitable slurrylike consistency. Instead of ammonium phosphate other foam-forming substances may be used.

If a fire arises in one of the rooms separated by the door, the paste 32 will blister, so that foam is produced in the chink 30 between the door and the frame, whereby the fire is prevented from penetrating through this chink. ilf the door has a layer or an inlay of incombustible material, the door will resist the fire at any rate for half an hour without impermissible increase of temperature in the adjoining room. In the course of this time the fire would be able to penetrate through the frame, if special precautions had not been taken.

The insertion of the asbestos strip 22 has proved to prevent the frame from being rapidly burnt through, when the strip, as shown, is positioned in proximity to the rebate engaged by the door, seeing that between the foam and the asbestos strip there will exist only a narrow wooden bridge, along which the carbonization and combustion of the material will proceed very slowly.

Besides the strip 22 shown one or more similar strips canbe inserted, either at the side of or at the edge of the strip 22, it being expedient, however, between the individual strips to leave a space occupied by wood, so that wood can still be glued to wood at places spaced along the depth of the frame, whereby adhesion between the individual layers of Wood is ensured.

In Fig. 2 there is inserted a strip 36 of the same material as the strip 22 between the frame 12 and an architrave 34 at the side of the frame, where the door 1'0 is found. The strip 36 will also contribute to retarding a burning through, especially if a hollow space has been left etween the frame 12 and the surrounding brickwork 38, which will often be the case in practice.

In Fig. 3 is shown an embodiment, whereby several strips have been embedded in the franc itself as mentioned in the foregoing. In this figure the designations it), 12, 18, 20, 24, 26, 28, 30, 32, 34, and 33 signify the same as before. At the adjoining face the two wooden layers 18 and 2d are provided with low and wide grooves, which are displaced in relation to each other, and wherein there are arranged strips, 40 and 42 respectively, of inorganic material, suitably a material which is heatinsulating besides being incornbustible, e.g. asbestos. The strip 42 has substantially the same position as the strip 22 mentioned in connection with Fig. 2. The wooden layers 18 and 20 are in direct contact at both edges of the strips 40 and 42, which is expedient with a view to obtaining a reliable agglutination. of said layers; At the edge of the strip 42 which faces the strip 40 there are produced from the adjoining face between the layers 18 and 20 opposite narrow grooves in both layers, e.g. with the use of a wobble saw. In the said grooves there is inserted a strip 44 of the same material as the strips mentioned in the foregoing.

As will appear from the structural design described in the foregoing, the strip 42 is parallel with the face 26 of the rebate in the frame, and the strip 44 is parallel with the other face 24 of the rebate. Between the strips 42 and 44 on one hand and the rebate formed of the faces 24 and 26 on the other hand, there will thus be produced an angular bridge of wood, along which an arising fire can only advance slowly, provided that there is tightness between the door and the frame and that the door material can prevent the fire from penetration. Means whereby this can be obtained have been mentioned in the foregoing. In this embodiment the groove for the paste 32 is undercut.

. It should be noted that the strip 40, which is positioned farthest away from the door chink 30 will to some degree be able to prevent the advance of the fire through the part of the frame, which turns downward in Fig. 3. Besides, this strip imparts an approximate symmetry to the cross section of the frame and thereby counteracts warping of the wooden material.

Instead of one strip 44 only, several such strips can be provided in mutually parallel or substantially parallel positions.

It has been mentioned in the foregoing that the effect aimed at by the invention is obtained by providing a narrow bridge, which is limited at either side by incom bustible material. Experiments have proved that a major reason for the delayed combustion is that the air and consequently its oxygen, which is indispensable for the combustion, will only slowly be admitted to the place of combustion, seeing that with the burning away of the material in the bridge a crevice is produced, to the bottom of which the air flow produced by the fire will reach only partially.

As other examples of incombustible material which can be used in accordance with the above reflections, and which has proved expedient in practice, mention shall be made of fibre cement, the fibres of which consist of glass filaments or so-called rock-wool. The fibres admixed serve in known manner to increase the strength and reduce the friability. Many other inorganic materials, including metals, will also be useful, in solid as well as in divided or disintegrated forms.

Fig. 4 shows a particularly suitable manner of disposing the foam-producing paste in connection with a door with inlaid incombustible material. The door is made of two layers 46 and 48 of wood or other combustible material, between which said layers there is provided an inlay t) aifording protection against the burning through of the door. This layer extends as far as to the edge face 52 of the door. In case of fire at one side of the door, the advance of the fire will be retarded or stopped by the inlay 50. The door is placed as usual in a frame 54, which may be constructed as mentioned in connection with Fig. 2 or 3. The numeral 56 denotes the rebate, which engages the border of the closed door.

In the edge face 52 of the door there is produced an undercut groove 58, which is filled with foam-producing putty or paste 60. The groove 58 is provided at the side of the inlay 50 which faces inwardly. At the other side of the inlay 50 there is provided in the frame 54 a similar groove 62, which is likewise filled with foam-producing paste 64. The paste may be manufactured and have the composition as described in the foregoing. If a fire of prolonged duration arises, the wooden layer 46 or 48 at the side of the door where the fire is on will gradually be carbonized as far as to the protective inlay 50, and the paste, 64 or 60 respectively, which is provided at the same side, will be entirely consumed on account of theintense heat. At the same time the heat Y i 4 will reach the paste at the opposite side, which can still afford protection for some time by the production of foam.

If the fire arises at the interior side of the door, to be found lowermost in Fig. 4, it is expedient that the grooves 58 and 62 should be positioned as shown, i.e. so that the groove 58 at the edge face of the door is positioned within the protective inlay 50. The reason is that by such a fire the door will be inclined to curve outwards at the edges, and in such case the groove 58, if it were positioned at the opposite side of the inlay 50, might completely or partially be outside the outermost or top edge of the frame 54, so that all the foam produced would not enter the chink and part of it thereby become useless.

Having thus fully described my invention I claim as new and desire to secure by Letters Patent:

1. A wooden frame for fire-retarding and fire-proof doors, provided with a rebate engaged by and having an abutment face for the door when closed, at least one strip of incombustible material embedded in the wooden material of said frame in the proximity of said rebate, said abutment face for the door being provided with a groove filled with foam-producing paste.

2. A frame of combustible material for use in connection with fire-retarding and fireproof doors, said. frame being provided with a rebate engaged by the door when closed and formed by a face forming an abutment for the door and a second face perpendicular to said firstnamed face, said frame consisting of at least two interconnected layers of wood abutting on a third face parallel to said second face, at least one strip of inorganic incombustible material arranged at said third face completely enclosed by said two layers of wood and located in the proximity of said rebate.

3. A frame according to claim 2, in which said inorganic incombustible material consists of asbestos.

4. A frame of combustible material for use in connection with fire-retarding and fireproof doors, said frame being provided with a rebate engaged by theedge of the door when closed thereby leaving a chink, at least one strip of incombustible material extending longitudinally of said frame being embedded therein in the proximity of said rebate, and a groove filled with foam-producing paste in one of the faces adjacent to said chink.

5. A frame according to claim 2 in which one of the faces of the rebate is provided with a groove filled with a paste producing foam at a superatrnospheric temperature.

6. A frame according to claim 2 in which the door has fourth and fifth faces cooperating with the first and second faces, and at least one of the first, second, fourth and fifth faces is provided with a groove filled with a paste producing foam at a superatmospheric temperature.

7. A frame according to claim 6 in which the edge face of the door and the cooperating face of the rebate are both provided with grooves filled with a paste producing foam at a superatrnospheric temperature.

8. A frame according to claim 2 in which an architrave is secured to the edge of the frame pieces and a strip of incombustible material is positioned between the edge of the frame pieces and the architrave.

9. A frame of combustible material for use in connection with fire-retarding and fireproof doors, said frame being provided with a rebate engaged by the door when closed and formed by a face forming an abutment for the door and a second face perpendicular to said first-named face, said frame consisting of at least two interconnected layers of wood abutting on a third face parallel to said second face, at least two strips of inorganic incombustible material arranged at said third face completely enclosed by said two layers of wood and located in the proximity of said rebate, said strips being substantially perpendicular 'to each other.

5 of one of the strips is located in the proximity of one 634,739 edge of the other strip. 2,249,591

11. A frame according to claim 10, in which said two strips adjoin.

References Cited in the file of this patent UNITED STATES PATENTS 603,442 De Man May 3, 1898 6 Stearns Oct. 10, 1899 Allen July 15, 1941 FOREIGN PATENTS 7 Great Britain Feb. 23, 1939 

